Add ffmpeg system dependencies to fix audio processing

- Install ffmpeg and libsndfile1 in Dockerfile
- Fix "No such file or directory: 'ffprobe'" errors
- Enable proper audio format conversion for ML models

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Dockerfile

@@ -1,6 +1,12 @@
 # Use Python 3.10 for better package compatibility
 FROM python:3.10-slim
 
+# Install system dependencies (including ffmpeg for audio processing)
+RUN apt-get update && apt-get install -y \
+    ffmpeg \
+    libsndfile1 \
+    && rm -rf /var/lib/apt/lists/*
+
 # Create user for HF Spaces (required)
 RUN useradd -m -u 1000 user
 USER user